This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from my application entitled INKJET MULTIFUNCTION DEVICE CAPABLE OF REPAIRING MALFUNCTION OF A NOZZLE, AND A METHOD FOR MAINTAINING THE SAME filed with the Korean Industrial Property Office on May 16, 2001 and there duly assigned Serial No. 2001-26590.
1. Field of the Invention
The present invention relates to an inkjet correction device equipped with a scanner, a printing unit, and so on, and more particularly to an inkjet correction device having a function for repairing malfunctioning nozzles performing printing operations and a method for detecting the malfunctioning nozzles.
2. Description of the Related Art
An inkjet correction device, named a multifunction peripheral (MFP) or a multifunction device (MFD), refers to a multifunction product devised to enable additional functions related to printing at the same time with performing the functions of an inkjet printer. Such inkjet multifunction device, in general, includes a printing unit for printing certain shapes on sheets of paper, a scanner for scanning images and providing the scanned images to the printing unit, and a fax unit for receiving fax data transferred through the public switched telephone network and providing the received fax data to the printing unit, and the like.
The printing unit in the inkjet multifunction device is provided with a head having plural nozzles to perform printing jobs by jetting ink. During the repeated ink-jetting performance of the nozzles for printing jobs, nozzle-aging or other various factors cause the nozzles to malfunction in their performance of normal ink-jetting operations. If any of the nozzles is malfunctioning in its normal ink-jetting operations, white lines become present on printed output images.
The most common cause for a nozzle to malfunction is that the nozzle becomes clogged. In order to repair the malfunctioning nozzles, a method for the nozzles to purge with ink is employed in the conventional art. The purging is repeated the predetermined number of times, and, if the clogged nozzles are unclogged by the repeated spitting, the nozzles normally work on printing jobs when performing future printing jobs.
However, in the conventional method for repairing the malfunctions of nozzles as stated above, there exists a problem in that ink is wasted a lot since the purging is performed on all the nozzles in the head even in case that one or some of the nozzles are malfunctioning. Further, in case that ink is smoothly jetted with the nozzles repaired by the purging, paper, time and ink are wasted since the purging is repeatedly performed a predetermined number of times, regardless of whether the clog is fixed early in the purging process.
The present invention has been devised to solve the above problems, so it is an object of the present invention to provide a inkjet multifunction device capable of effectively repairing malfunctioning nozzles and prevent wasting of ink, paper, and time by selectively performing the purging only to malfunctioning nozzles.
In order to achieve the above object, an inkjet multifunction device according to the present invention includes a print unit equipped with plural nozzles for printing a certain test pattern on paper, a scanner for scanning the test pattern printed on the paper and a control unit for determining whether or not the respective nozzles malfunction based on the test pattern the scanner scans, and controlling the printing unit to purge only the malfunctioning nozzles.
Here, the control unit determines which nozzles are functioning nozzles corresponding to parts where colored dots are present out of parts of the test pattern, and deems a nozzle to be functioning if the corresponding part of the test pattern has a color brightness which is over a certain level.
In the meantime, the control unit repeatedly performs the control operation of the printing unit by a predetermined number of times to determine which nozzles are malfunctioning and purging only the defective nozzles of the printhead, stops the test steps for repairing nozzles if it is determined that all the nozzles normally operate after repetitive purging operations, and indicates to an external personal computer 33 and/or a display unit 51 in case that malfunctioning nozzles remain.
The test pattern includes a predetermined reference image being a reference for determining positions of an image to be tested, and the control unit determines a corresponding relation between the nozzle locations and parts of the image to be tested. Accordingly, the control unit exactly detects which nozzles are malfunctioning nozzles through the scanned image.
In the meantime, according to the present invention, a method for repairing malfunctioning nozzles in an inkjet multifunction device is provided which includes the steps of printing a predetermined test pattern on paper, scanning the printed test pattern; determining whether respective nozzles in a printing unit malfunction based on the scanned test pattern and performing a controlled, efficient purging of only the nozzles designated as being malfunctioning.
According to the present invention, the repair of the malfunction nozzles can effectively implemented by selectively performing ink purging only to malfunctioning nozzles, and the repetition of meaningless testing jobs can be prevented in case that the nozzles are all repaired.